Ah a common misconception is that a bigger engine requires better brakes, this is not the case, speed is speed regardless of wether it is v8 powered or lawnmower engine powered, your brakes do not need to do any extra work to reduce the car from 100mph to zero if you have more BHP,in fact you could have a gazillion BHP and still use the same brakes.

It is the extra weight of a bigger engine that requires a brake upgrade, more weight= more inertia thrown forward during braking, more friction and more effort required by the brakes to bring the extra weight to a stop.

The 2zz is going to be about the same weight as a 4age give or take 10 kgs so no brake upgrade needed.A nice st165 celica twin pot conversion always works very well though regardless.